I am sure this will not help much because I have to believe in all the time you have mowed this slope you have tried it... On the steeper part of my hill, I can easily drive up the hill, stoping ,starting and making turns (no more that 45 deg) and then I back down the hill. So I drive to the top and then turn the mower so that I come back down offset by 30 inches or so. This part of my slope is maybe 20 degrees. I can easily drive across it as long as I point the mower at like 40 degrees. I then either come back down it backwards or even turn the mower to point down and just let it go unto it levels out. the disclaimer is I dont have an acre of this ... anyway like I said I have to believe you have tried it. Also just in case you havent, be very light on the sticks when you stop and take off again. I can easily lift the front wheels a foot by hitting it full on. Also the other thing I did was to put snappers hig traction wheel kit(the tires looked like almost paddle tires with v ribs) on my mower from the start. This cured most of my slipage. Also there is another thread on this forum where the gentleman bought the RZT-S and claimed it worked very well on slopes. I am about to find out how well my country clipper I bought does on my same hill. I have a feeling I will be looking for similiar tires to the old snapper traction kit for it.